A sample processing apparatus that aspirates a sample in a sample container held in a sample rack to perform sample processing is known. The sample container may be of various types having different shapes such as inner diameters, outer shapes, lengths, and the like, and thus the aspirating operation and the like need to be changed according to the shape of the sample container when performing the aspirating operation and the like with respect to the sample container in the sample processing apparatus.
In a technique described in U.S. Patent Application Publication No. 200810050279A1, the type of sample container held in the sample rack is distinguished from a barcode attached to the sample rack, and the aspirating operation with respect to the sample container is executed according to the type of distinguished sample container.
However, in a facility that processes a very large number of samples such as a large hospital and an examination center, the barcode attached to the sample rack might get dirty or the barcode may come off from the sample rack while the sample rack is being repeatedly used. Even if the barcode is not peeled off, there is a risk of reading mistake by the barcode reader. In these cases, the barcode attached to the sample rack is not accurately read, and the type of sample container held in the sample rack may not be distinguished.